The present invention relates to an engine and drive system, which may be used together or separately.
Internal combustion engines are well known and widely used. However, for several reasons, inherent in their basic design parameters, they are not as efficient as they could be.
One disadvantage of conventional internal combustion engines is that the moment of combustion is at top dead centre in the cycle, where the piston rod is at the most disadvantageous position, i.e. perpendicular to the piston face, and hence presenting a more rigid assembly. Thus the efficiency of the engine can never be perfect, and wear on the end bearings may be increased.
Another disadvantage is the high speed of rotation of the crankshaft. Usually, for most practical purposes, the speed must be reduced by gearing down, thus contributing further to toss of efficiency.
It is also the case that standard internal combustion engines are complicated with a large number of moving parts. The fewer parts there are, the fewer there are to go wrong. Hence, it is an object of the present invention to provide an engine which has fewer moving parts and offers a higher possibility of higher efficiency.
According to a first aspect of the present invention there is provided an engine comprising at least two open ended curved cylinders disposed in toroidal arrangement with respect to a central pivot point, at least two piston arms pivoted about said point, at least four pistons each one adapted to cooperate with one end of a respective cylinder and arranged in pairs so mounted to a piston arm as to face tangentially one away from the other for alternate engagement with adjacent ends of two of said at least two cylinders.
Preferably two piston arms are provided, each journalled for pivoting movement about said point and each having one said pair of pistons mounted at each end of the arm.
Advantageously, there are provided four cylinders and eight pistons.
Each piston arm may pivot through an angle of up to 33xc2x0, ideally 28xc2x0, 24xc2x0, or 21xc2x0.
The cylinders are arranged equiangularly about the periphery of a circle defined by said piston arms, and each may comprise a portion of either a circular or elliptical cross-section torus.
The two piston arms are disposed transversely and may be orthogonal at a median point in their respective reciprocating pivotal movements.
Each cylinder is provided with an inlet port adjacent one end and an exhaust port adjacent an opposite end, each closed by a respective piston during its inward travel and openable during the outward travel of said piston.
Movement of said pistons may be regulated by power take off/timing means which comprise a central axle and an arm rotatable thereabout, each diametrically opposed end of said arm being so connected by lever means to one of said two piston arms that the reciprocating pivotal movement of the piston arms is converted to continuous rotary movement of the central axle.
Optionally, said power take-off means may be provided with flywheel means to smooth out and maintain the rotary movement of the central axle.
According to another aspect of the present invention, there is provided a drive system comprising a first powered shaft, a second unpowered shaft spaced from and linked to said first shaft, at least one rotatable member freely journalled to said second shaft, at least one drive arm extending from said first shaft and at least one connection link means to connect a remote end of the or each said drive arm with a point on the or a respective one of said rotatable member spaced from said second shaft.